text: //@ skip if not $jitTests
  //@ defaultNoEagerRun
  "use strict";
  
  let log2OfHalf = Math.log2(0.5);
  
  let validInputTestCases = [
      // input as string, expected result as string.
      ["undefined", "NaN"],
      ["null", "-Infinity"],
      ["1", "0"],
      ["0", "-Infinity"],
      ["-0.", "-Infinity"],
      ["0.5", "" + log2OfHalf],
      ["Math.PI", "" + Math.log2(Math.PI)],
      ["Infinity", "Infinity"],
      ["-Infinity", "NaN"],
      ["NaN", "NaN"],
      ["\"WebKit\"", "NaN"],
      ["\"0.5\"", "" + log2OfHalf],
      ["{ valueOf: () => { return 0.5; } }", "" + log2OfHalf],
  ];
  
  let validInputTypedTestCases = validInputTestCases.map((element) => { return [eval("(" + element[0] + ")"), eval(element[1])] });
  
  function isIdentical(result, expected)
  {
      if (expected === expected) {
          if (result !== expected)
              return false;
          if (!expected)
              return (1 / expected) === (1 / result);
  
          return true;
      }
      return result !== result;
  }
  
  
  // Test Math.log2() without arguments.
  function opaqueLog2NoArgument() {
      return Math.log2();
  }
  noInline(opaqueLog2NoArgument);
  noOSRExitFuzzing(opaqueLog2NoArgument);
  
  function testNoArgument() {
      for (let i = 0; i < 1e4; ++i) {
          let output = opaqueLog2NoArgument();
          if (output === output) {
              throw "Failed opaqueLog2NoArgument";
          }
      }
      if (numberOfDFGCompiles(opaqueLog2NoArgument) > 1)
          throw "The call without arguments should never exit.";
  }
  testNoArgument();
  
  
  // Test Math.log2() with a very polymorphic input. All test cases are seen at each iteration.
  function opaqueAllTypesLog2(argument) {
      return Math.log2(argument);
  }
  noInline(opaqueAllTypesLog2);
  noOSRExitFuzzing(opaqueAllTypesLog2);
  
  function testAllTypesCall() {
      for (let i = 0; i < 1e3; ++i) {
          for (let testCaseInput of validInputTypedTestCases) {
              let output = opaqueAllTypesLog2(testCaseInput[0]);
              if (!isIdentical(output, testCaseInput[1]))
                  throw "Failed testAllTypesCall for input " + testCaseInput[0] + " expected " + testCaseInput[1] + " got " + output;
          }
      }
      if (numberOfDFGCompiles(opaqueAllTypesLog2) > 2)
          throw "We should have detected log2() was polymorphic and generated a generic version.";
  }
  testAllTypesCall();
  
  
  // Test Math.log2() on a completely typed input. Every call see only one type.
  function testSingleTypeCall() {
      for (let testCaseInput of validInputTestCases) {
          eval(`
              function opaqueLog2(argument) {
                  return Math.log2(argument);
              }
              noInline(opaqueLog2);
              noOSRExitFuzzing(opaqueLog2);
  
              for (let i = 0; i < 1e4; ++i) {
                  if (!isIdentical(opaqueLog2(${testCaseInput[0]}), ${testCaseInput[1]})) {
                      throw "Failed testSingleTypeCall()";
                  }
              }
              if (numberOfDFGCompiles(opaqueLog2) > 1)
                  throw "We should have compiled a single log2 for the expected type.";
          `);
      }
  }
  testSingleTypeCall();
  
  
  // Test Math.log2() on constants
  function testConstant() {
      for (let testCaseInput of validInputTestCases) {
          eval(`
              function opaqueLog2OnConstant() {
                  return Math.log2(${testCaseInput[0]});
              }
              noInline(opaqueLog2OnConstant);
              noOSRExitFuzzing(opaqueLog2OnConstant);
  
              for (let i = 0; i < 1e4; ++i) {
                  if (!isIdentical(opaqueLog2OnConstant(), ${testCaseInput[1]})) {
                      throw "Failed testConstant()";
                  }
              }
              if (numberOfDFGCompiles(opaqueLog2OnConstant) > 1)
                  throw "We should have compiled a single log2 for the expected type.";
          `);
      }
  }
  testConstant();
  
  
  // Verify we call valueOf() exactly once per call.
  function opaqueLog2ForSideEffects(argument) {
      return Math.log2(argument);
  }
  noInline(opaqueLog2ForSideEffects);
  noOSRExitFuzzing(opaqueLog2ForSideEffects);
  
  function testSideEffect() {
      let testObject = {
          counter: 0,
          valueOf: function() { ++this.counter; return 0.2; }
      };
      let log2Result = Math.log2(0.2);
      for (let i = 0; i < 1e4; ++i) {
          if (opaqueLog2ForSideEffects(testObject) !== log2Result)
              throw "Incorrect result in testSideEffect()";
      }
      if (testObject.counter !== 1e4)
          throw "Failed testSideEffect()";
      if (numberOfDFGCompiles(opaqueLog2ForSideEffects) > 1)
          throw "opaqueLog2ForSideEffects() is predictable, it should only be compiled once.";
  }
  testSideEffect();
  
  
  // Verify log2() is not subject to CSE if the argument has side effects.
  function opaqueLog2ForCSE(argument) {
      return Math.log2(argument) + Math.log2(argument) + Math.log2(argument);
  }
  noInline(opaqueLog2ForCSE);
  noOSRExitFuzzing(opaqueLog2ForCSE);
  
  function testCSE() {
      let testObject = {
          counter: 0,
          valueOf: function() { ++this.counter; return 0.2; }
      };
      let log2Result = Math.log2(0.2);
      let threelog2Result = log2Result + log2Result + log2Result;
      for (let i = 0; i < 1e4; ++i) {
          if (opaqueLog2ForCSE(testObject) !== threelog2Result)
              throw "Incorrect result in testCSE()";
      }
      if (testObject.counter !== 3e4)
          throw "Failed testCSE()";
      if (numberOfDFGCompiles(opaqueLog2ForCSE) > 1)
          throw "opaqueLog2ForCSE() is predictable, it should only be compiled once.";
  }
  testCSE();
  
  
  // Verify log2() is not subject to DCE if the argument has side effects.
  function opaqueLog2ForDCE(argument) {
      Math.log2(argument);
  }
  noInline(opaqueLog2ForDCE);
  noOSRExitFuzzing(opaqueLog2ForDCE);
  
  function testDCE() {
      let testObject = {
          counter: 0,
          valueOf: function() { ++this.counter; return 0.2; }
      };
      for (let i = 0; i < 1e4; ++i) {
          opaqueLog2ForDCE(testObject);
      }
      if (testObject.counter !== 1e4)
          throw "Failed testDCE()";
      if (numberOfDFGCompiles(opaqueLog2ForDCE) > 1)
          throw "opaqueLog2ForDCE() is predictable, it should only be compiled once.";
  }
  testDCE();
  
  
  // Test exceptions in the argument.
  function testException() {
      let counter = 0;
      function opaqueLog2WithException(argument) {
          let result = Math.log2(argument);
          ++counter;
          return result;
      }
      noInline(opaqueLog2WithException);
  
      let testObject = { valueOf: () => {  return 0.1; } };
      let log2Result = Math.log2(0.1);
  
      // Warm up without exception.
      for (let i = 0; i < 1e3; ++i) {
          if (opaqueLog2WithException(testObject) !== log2Result)
              throw "Incorrect result in opaqueLog2WithException()";
      }
  
      let testThrowObject = { valueOf: () => { throw testObject; return 0.1; } };
  
      for (let i = 0; i < 1e2; ++i) {
          try {
              if (opaqueLog2WithException(testThrowObject) !== 8)
                  throw "This code should not be reached!!";
          } catch (e) {
              if (e !== testObject) {
                  throw "Wrong object thrown from opaqueLog2WithException."
              }
          }
      }
  
      if (counter !== 1e3) {
          throw "Invalid count in testException()";
      }
  }
  testException();
  